The invention relates to a battery pack for an electric power tool, in particular hand-guided power tool, such as a hedge trimmer, a motor chain saw, a cut-off machine, a brush or grass trimmer or the like, comprising a housing with a housing cover, a plurality of individual battery cells arranged in the housing that are electrically conductingly connected to one another and an electronic circuit for monitoring operating parameters of the battery cells, the electronic circuit being disposed in the battery pack housing and arranged on a circuit board.
Battery packs are generally known and are comprised of a plurality of battery cells arranged in a battery pack housing and connected electrically in a suitable way parallel or in series with one another in order to provide a desired battery pack voltage or battery pack power.
As battery cells lithium ion, lithium polymer or the like cells are employed in order to obtain long operating times of the electric devices operated therewith.
Battery cells that are based on lithium require monitoring circuits in order to reliably prevent, on the one hand, exhaustive discharge that would destroy the battery cells and, on the other hand, to protect the cell by switching it off when currents are too high or temperatures are too high. Such protective circuits are comprised of electronic components arranged on a circuit board and are disposed together with the battery cells in the housing of the battery pack.